Solar Decathlon: part 2

What I go to the Solar Decathlon for is the toys. After 5 decathlons you can imagine that I'm running low on things that stand out and really impress me.

Two of the houses were showing off their dehumidifiers. The one below is filled with white plastic shells that you could sort of describe as ping pong ball skeletons. They aren't important, though. They're just surface area. The desiccant is a lithium chloride salt liquid that pours over the plastic. It draws the moisture from the air and then is pumped to another location where it's heated to release the water it captured from the air. The heat is provided by solar water heaters on the roof which goes on to be used in showers and whatnot.

lithium chloride salt dehumidifier

Another school was using liquid calcium chloride salts. However, theirs was still using a system that the school using the lithium chloride tried and rejected. The calcium chloride was just running down the window. The added surface area of the balls improved efficiency of the dehumidifier.

Thermal mass has always been popular for climate control systems. They soak up heat during the day that they release at night and take the cool from the night and release it during the day. Stone is great for that. Water does a good job, too. That's why coastal areas have more moderate temperatures than mid-continent areas that suffer from extreme temperatures on both ends of human tolerance.

This all concrete house has LOTS of thermal mass.

rotating chambers filled with phase change materials

If you want to get fancier you can invest in some phase change materials. These vertical thingies are filled with one. I forget whether they were using palm oil or paraffin wax. One school was using one and another was using the other. But there's several kinds. Usually fat or oil based. They tend to change from solid to liquid close to room temperature. This enhances their ability to carry their temperature over longer periods.

I just like the door in this utility closet. The door came from a New York City subway car. Behind it is a well insulated water tank.

I thought I got a picture of this, but apparently not. One house had cylindrical solar arrays. I'd seen some diagrams online proposing the idea awhile back, but didn't know they were in production. Instead of having a flat surface that is only at it's ideal angle relative to the sun for part of the day these tubes are at their optimal angle all the time. You can see some and read more here.

Tomorrow we look at the plants.